To prevent unauthorized duplicates or alteration of documents, indicia or a background pattern can be provided. For instance, documents including tickets, checks, passports, banknotes, currency, product labels and the like may be easily counterfeited if counterfeit-deterring images are not employed. The indicia imposed upon a document is typically performed by a printing process such as offset printing, lithography, letterpress or other like mechanical systems or through a variety of photographic methods, by xeroprinting, and a host of other methods. The patterns or indicia may be reproduced with ordinary inks, from special inks which may be magnetic, fluorescent, or the like, from powders which may be baked on, from light sensitive materials such as silver salts or azo dyes, and the like. Most of these patterns placed on sheet materials depend upon complexity and resolution to avoid ready duplication. Consequently, they add an increment of cost to the sheet material without being fully effective in many instances in providing the desired protection from unauthorized duplication or alteration.
Various methods of counterfeit-deterrent strategies have been suggested including Moire-inducing line structures, variable-sized dot patterns, latent images, see-through bars, bar codes, and diffraction based holograms. However, none of these methods employs a true encoded image or the added security benefits derived therefrom.
The instant inventor has been awarded a number of patents on various encoding processes including U.S. Pat. Nos. 3,937,565; 3,524,395; 4,092,654; 4,198,147; 4,914,700; and 5,708,717 the contents of which are herein incorporated by reference. U.S. Pat. No. 5,708,717 discloses a system and method for a Digital Anti-counterfeiting Software Method and Apparatus wherein a latent image was placed onto a source image implemented by a computer software program, such that the latent image is only visible when viewed through a special decoder lens. These principles and embodiments are hereby incorporated by reference.
The greater the frequency the greater the complexity of the encoding and thus the greater the difficulty in counterfeiting a product that has been encoded utilizing the inventor's technology. However, it has been found that the use of images encoded by multiple frequencies making them readable by different lens or a combination thereof has produced a new and unique level of encoding. Accordingly, what is needed in the art is a method and apparatus for producing multiple counterfeit-deterring images that can be decoded individually or together by a lens having multiple active decoding sections or layers, or by use of a combination of lenses. The multiple images provide an increasingly complex encoding of latent images for enhancing security.
The instant invention includes a lens having at least two active decoding sections wherein, each section may have a unique frequency based upon the curvature of that lens. For the purposes of this invention, a lens is defined as any device capable of altering the character of transmitted or reflected light, in accordance with specifically defined parameters, e.g. lenticular parameters. The anti-counterfeiting software will be used to match the lens parameters thereby providing an encoding of a latent image or images(s) at least once, each encoding being a function of the parameters of a section of the decoding lens having specific frequency and/or lens curvature parameters. The angle of the curvature further permits a lower frequency, but when coupled to the double encoding, results in an increased complexity to the encoded latent image. Further, by modifying the curvature, the thickness of the lens corresponding to a particular frequency can be modified providing a paper thin lens. Thus, in one embodiment the latent images can only be viewed through a multi-section lens decoder having a section with parameters that corresponds to each encoding. In another embodiment different latent images found within the same image, can be decoded by use of multiple lenses allowing different levels of security. As a result, the inventor has significantly enhanced the anti-counterfeiting aspect of his invention.